Love can be a mysterious and powerful force, making it difficult to pinpoint the exact moment when it takes hold. In this article, we'll dive into the science behind falling in love, exploring the role of neurotransmitters and hormones in the process.
Three neural systems that drive attraction and falling in love
Three neural systems drive attraction and falling in love, helping answer the question, "how do you know you love someone?" Love is not primarily an emotion but a motivation system (i.e., a system oriented around the planning and pursuit of a specific want or need) designed to maintain a relationship with a specific partner. Neuroscientists believe that this motivation arises from three neurotransmitters that actively play a role in the brain chemistry of someone who is falling in love. They are dopamine, norepinephrine, and serotonin. Each neurotransmitter is activated during a specific stage in dating. What is so fascinating is that they can produce overwhelmingly strong symptoms such as insomnia, loss of appetite, and even Obsessive Compulsive Disorder (OCD). Let's take a look at each of these neurotransmitters and how they play a role in falling in love.
The Role of Dopamine: How Do You Know You Love Someone?
Dopamine is most prevalent in the beginning ‘attraction’ stage of a relationship when everything is new and exciting. It is a natural occurrence for the novelty to wear off as the relationship progresses toward the ‘attachment’ phase. However, couples can prolong the rush of dopamine by taking on novel activities together (learning a new skill, trying a new sport, or visiting a new city together, for example).
Dopamine, known as the “feel-good chemical,” plays a big role in reward-seeking activities. It is responsible for the high we feel when we do something daring, like skydiving out of a plane or bungee jumping off a bridge, or the satisfaction we feel after we play our favorite sport or eat our favorite meal.
Studies show that rewards increase levels of dopamine. This is what stimulates our desire to spend every waking moment with our sweetheart — to seek feelings of love, ecstasy, and excitement. This leads us to depend on that person for our emotional satisfaction. In other words, we become highly addicted to feelings of love.
After all, it is dopamine that is prevalent in addictive behaviors. Scientists have discovered that dopamine has the same effect on brain chemistry as cocaine. Cocaine acts by blocking the removal of dopamine from the synapse, which results in an accumulation of dopamine and an amplified signal to the receiving neurons. This is what causes the initial euphoria commonly reported by cocaine users. People in love also experience an increase in dopamine and therefore a similar euphoria.
Dopamine is also responsible for what drives us into mania, anxiety, and fear when we think our romance is in jeopardy. When our emotional satisfaction is threatened, we desperately try to win back the object of our love and stabilize our well-being.
Norepinephrine: Stress Hormones and Falling in Love
Norepinephrine and cortisol act as stress hormones that are released into the bloodstream when the brain perceives that a stressful event has occurred. Love is accompanied by increased levels of these stress hormones. Why? Well, it appears that stress is the trigger for a quest for pleasure, proximity, and closeness. Let me explain…
During the early stages of a relationship, there is a moderate amount of stress due to fear or dislike of anything new and unfamiliar. In other words, it can be stressful not knowing where your relationship is heading. All you know is that you don’t want anything threatening your current state of bliss.
Our body’s natural response is to enter into a physiologic state of alertness (caused by cortisol and norepinephrine) to help overcome this fear. In fact, this stress response appears to be the most important factor in the formation of social contact and attachment. Besides alertness, it can also cause insomnia, loss of appetite, increased attention, increased memory for new stimuli, increased heart rate, sweating, and trembling. Sounds fun, right?
Serotonin: The Connection Between Love and Obsessive Thoughts
Finally, we reach the third neurotransmitter, serotonin. Serotonin is the key culprit for obsessive thinking of our beloved. Research shows that people in love have the same levels of serotonin that are found in people suffering from Obsessive Compulsive Disorder (OCD). This would explain why serotonin is linked with obsessive thinking patterns.
A team of Italian scientists, under the leadership of Dr. Donatella Marazziti, a psychiatrist at the University of Pisa, took blood samples from twenty people “in love,” twenty people suffering from the compulsive disorder, and twenty people who were not in love and had no psychiatric problems. They found that people suffering from OCD and people who were in love both had 40 percent less serotonin than the group of people who were not in love and did not have any psychiatric problems.
Interestingly, the people who were in love were tested again twelve months later and found that after the initial intensity of love faded, their serotonin levels returned back to normal.
Doctors now treat OCD with SSRIs (selective serotonin reuptake inhibitors)— Prozac or Zoloft— to elevate serotonin levels. Like with any drug, serotonin-enhancing drugs have surprising side effects. Dr. Helen Fisher, Biological Anthropologist, says, “Like drugs that blur your vision, serotonin-enhancing medications can potentially blur a woman’s ability to evaluate mating partners, to fall in love, and to sustain an enduring partnership.”
In one case study, led by Dr. Helen Fisher, a 35-year-old woman was prescribed serotonin-enhancing medication after suffering from depression and anxiety. Little did she know, it would affect her whole marriage. Her libido diminished, she was unable to orgasm, and she ultimately decided this meant she no longer loved her husband and filed for divorce. However, when she cycled off the medication, she realized the root cause and reunited with her husband. This shows you how powerful serotonin can be in relationships.
So powerful, in fact, that I would say serotonin is the most important component of falling in love. It is responsible for literally changing the way you think. It diverts your mind and bounds you to think of your love and nothing else, setting you on a path with the end goal being to fall in love.
Love electrifies neurotransmitters in the mind, activates our body's stress hormones, and consumes the senses. Dopamine sends waves of ecstasy and excitement throughout our bodies. Norepinephrine and cortisol flood our system, giving us bouts of hyper-focused energy and insomnia. Serotonin levels throw us into an obsessive-compulsive state.
Nine years after experiencing this kind of intense, overwhelming love (as first loves always are), I realize how insane love is. It’s highly addictive, makes us temporarily insane, and has dramatic effects similar to jumping out of a plane or snorting cocaine. My motto, “Knowledge is power” applies. When we know what’s happening in our minds and bodies during this erratic time, we are capable of navigating our relationships with more peace, certainty, and sanity.
If you are still doubting whether or not you love someone, there are questions to ask yourself to decipher if you are truly falling in love. For example, Do you constantly think about the person? Do you feel a sense of longing or excitement when you are with them? Do you feel a sense of comfort and safety around them?
Keep in mind, people may fall in love at different times in the relationship. One may fall fast, without hesitation, early on in the relationship, while the other may take time to open up to the other person and allow themself to be vulnerable enough to fall in love (and express that love). It is important to take your time and enjoy the journey, not rushing your partner into feeling or expressing anything. Be patient and remember everyone has their own journey and way of feeling and expressing those feelings.
Understanding the science behind love can give you valuable insights into your own feelings and relationships. By recognizing the role of neurotransmitters and hormones in the process, you can better answer the question: how do you know you love someone? Ultimately, love is a complex and transformative experience, unique to each individual and their journey.
Aron A, Paris M, Aron EN. Falling in love: Prospective studies of self-concept change. J Pers Soc Psychol, 1995. 69:1102–12.
Griffin MG, Taylor GT. Norepinephrine modulation of social memory: Evidence for a time-dependent functional recovery of behavior. Behav Neurosci, 1995. 109:466–73.
Davidson, R.J. Complexities in the search for emotion-specific physiology. In P. Ekman and R.J. Davidson (eds.), The Nature of Emotion: Fundamental Questions. New York: Oxford University Press, 1994. Print.
Webster, Richard. Soul Mates: Understanding Relationships Across Time. Woodbury: Llewellyn Publications, 2004. Print.
Fisher, Helen. Why We Love: The Nature and Chemistry of Romantic Love. New York: Henry Holt Company, 2004. Print.
Fisher, Helen, Arthur Aron, Debra Mashek, G Strong, Haifang Li, and Lucy Brown. “Defining the Brain Systems of Lust, Romantic Attraction, and Attachment.” Archives of Sexual Behavior, 31.5 (2002): P 413-419. Print.
Fisher, Helen, and J. Anderson Thomson, Jr. “Lust, Romance, Attachment: Do the Side Effects of Serotonin-Enhancing Antidepressants Jeopardize Romantic Love, Marriage, and Fertility?” Evolutionary Cognitive Neuroscience. Cambridge, MA: MIT Press, 207. P 245-283. Print.